Field of the Invention
The invention relates to a process for printing a successive row of numbers of bar code 2/5 interleaved and a device for performing the process.
Bar codes are being used increasingly for machine-readable marking of goods. Various codes exist, of which the so-called 2/5 interleaved offers the advantage of a high information density, since it uses not only the arrangement and size of the bars but also those of the intermediate gaps as information carriers.
With most numeric or alphanumeric codes, the individual numbers or letters are coded by a finite group of bars that are then followed by another group for the next number or the next letter. With coding with a successive row of numbers, therefore, e.g., with numbering of a series of articles from 01 to 99, a counter, usual in principle, can thus be used in which the units, then the tens and optionally the hundreds can be shifted stepwise at each printing operation.
The high information density of code 2/5 interleaved (overlapped) is based essentially on the fact that in each case two numbers are coded by a closed group of bars, the first of which is reproduced by the size and arrangement of the bars and the second by the size and arrangement of the spaces. With a usual mechanical counter, a printing of a successive row of numbers is thus not possible, since a stepwise change in the size and arrangement of the bars simultaneously changes the size and arrangement of the spaces contained between these bars, i.e., the two numbers contained in one bar group interleave in each other and form one unit. With printing of successive numbers 01 to 99, a print wheel with 99 different code formats would thus theoretically be necessary.
It is indeed easily possible to store the different code formats in a data-processing unit and to print them out with a laser printer or the like, but printers of this type achieve only about 1,000 impressions per hour, while with printing of a successive row of numbers with a mechanical printing unit, at least 30,000 printing operations per hour are possible.
The invention is thus based on the project of providing a process and a device that make it possible to print the 2/5 interleaved code in a successive row of numbers with a mechanical printing unit with limited construction expense.